[RedDevil]

It is even more subtle than that. In fact both the high pressure and the air-water interface have a function here.

When a boat moves through the water it needs to put aside the same amount of of water that it displaces. A 10.000 ton ship has to move 10.000 tons of water aside.
It requires a lot of force to set that amount of water in motion. That force is pressure; it needs to be higher than its surroundings. Once the water is moving aside its momentum will cause it to make way for the steadily increasing cross section area of the ship's bow.
When the bow finally reaches full width and the sides bend straight the water is forced to stop moving aside, creating low pressure. You can see that for yourself on any ship in motion; at the point where the hull straightens the water level will be slightly below the water line.

The protruding bulb forces itself through the water. As the water around it is not yet moving aside the pressure rises sharply, which accelerates the mass of water flowing aside and up.
But what goes up must come down. While the water that moves aside keeps doing that, the water on top recedes and transfers into sideways motion. Just at the point where it becomes level again the sharp edge of the bow cuts in. As the water is already moving down and aside it meets less resistance than it would have without the bulb.

The bulb serves in making the transition from a body of water in rest to that same body moving sideways more gentle. There is a close relationship between the rate at which the cross section area of a body moving through water varies and the resistance it meets. As you see the variation of the cross section as a function, you need to keep the second order derivato of that function as close to zero as possible.

You cannot fully apply aquadynamic rules to aerodynamics. But the base principle that when you move something through the air, the momentum of the displaced air does influence resistance and you have to keep its transitions gradual, holds true.
The first fighter jets that were able to break the barrier of sound could only just do that, and not for long due to massive fuel consumption. The breaktrough tor really fast jets came with the realization that the wings of the planes displaced air, and at supersonic speeds that air had nowhere to go. This was solved by narrowing down the fuselage by a comparable amount; the so-called Coke contour. (other solutions were swept wings and the Delta wing, which made the wings themselves displace air gradually).

In car terms, this means that you can compensate for anything you move into a stream by making a dent in another part close by so the total area does not change much, and the momentum of the air at some distance to the car is not disturbed.
Or you can gradually build up and recede the area just before and after the intruding bit for the same effect; like the leading and trailing spoilers at the wheels of low Cd concept cars. They work because of this principle.

Phew!
Anyway, a ships bulb bow would not work on a car; there's no water to lift and fall back. That said, it is the very mod I'm planning to do to my car.
I will replace my lower grill block by a bulge that slightly protrudes the front bumper and license plate of my 2011 Insight. It should curve back towards the sides to make a flush transition with the 45 degree angle of the front bumpers edges. But will not really stick out like a ships bow.
Before I do so I wil do some other simple mods and get some data on the MPG that yields as a base for further testing. Hope I can give some results soon.